[SWODY2] SWODY2

[SWODY2 at goshenarc.org]

ACUS02 KWNS 111740
SWODY2
SPC AC 111738

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1238 PM CDT TUE MAY 11 2004

VALID 121200Z - 131200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 65 ENE
MQT ESC OSH UIN JEF SGF UMN OKC FSI LTS GAG DDC GCK LAA LHX 30 NE
COS 30 SE CYS 20 S SNY 55 N RSL CNK BIE OMA 40 WSW SPW FSD ATY 50 E
FAR INL.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 NE MSS RUT ISP
...CONT... WAL RIC DAN GSO CAE 75 W SAV MGR PFN ...CONT... GLS LFK
TYR DUA 45 N MWL BWD SJT CDS 30 E LBL TAD CNY DPG OWY BNO PDT ALW
BTM 30 NE RAP MHN LBF EAR GRI OLU OFK MHE HON GFK 25 WNW RRT.

...THERE IS A SLGT RISK OF SVR TSTMS UPPER MS VALLEY TO CENTRAL HIGH
PLAINS...

...SYNOPSIS...
IN MID-UPPER LEVELS...MEAN TROUGH WILL PERSIST OVER WRN CONUS BUT
BEGIN TO DEAMPLIFY SOMEWHAT LATE IN PERIOD.  EMBEDDED CYCLONE -- NOW
EVIDENT ON MOISTURE CHANNEL IMAGERY OVER WRN MT -- IS FCST TO FILL
SLOWLY AS IT DRIFTS ENEWD ACROSS MT THROUGH DAY-2.  SHORTWAVE TROUGH
NOW LOCATED SW OF THAT LOW OVER NV IS EXPECTED TO FOLLOW
CYCLONICALLY CURVED PATH TOWARD NRN PLAINS BY 13/00Z...THEN DEVELOP
ITS OWN CYCLONIC CIRCULATION AND TAKE OVER AS PRIMARY MID/UPPER LOW
AS IT MOVES INTO MANITOBA/ONT BORDER REGION LATE IN PERIOD.  A FEW
SHORTWAVE PERTURBATIONS MAY EJECT NEWD AMIDST ZONE OF SWLY
FLOW...BUT CONFIDENCE IS LOW IN ANY MODEL PROGS OF SUCH SMALL SCALE
FEATURES THIS FAR IN ADVANCE.  IN ANY EVENT...BROAD BELT OF ENHANCED
MID-UPPER FLOW -- E.G. 65-75 KT AT 500 MB AT 12/18Z -- WILL
CONTRIBUTE TO FAVORABLE DEEP-LAYER SHEAR FOR SEVERE OVER LARGE SWATH
OF CENTRAL CONUS.

AT SFC...CYCLONE NOW OVER WRN SD WILL WEAKEN SOMEWHAT TODAY WITH
CYCLOGENESIS FARTHER S OVER CENTRAL HIGH PLAINS.  HOWEVER...NRN LOW
SHOULD STRENGTHEN CONSIDERABLY AGAIN AROUND BEGINNING OF PERIOD --
OVER WRN/NRN MN...AS SHORTWAVE TROUGH APPROACHES. 
MEANWHILE...TRAILING COLD FRONT WILL MOVE SEWD OVER CENTRAL PLAINS
AND UPPER MS VALLEY.  FRONT SHOULD REACH CENTRAL GREAT LAKES...NRN
IL/MO...NWRN OK AND NERN NM BY END OF PERIOD.  FRONT AND DRYLINE
SHOULD INTERSECT AT SRN CYCLONE -- EXPECTED INVOF SRN KS/CO BORDER
AT 13/00Z.  DRYLINE WILL EXTEND SEWD ACROSS WRN OK THEN SSWWD
THROUGH W TX.

...UPPER MIDWEST TO CENTRAL PLAINS...
POTENTIAL FOR EARLY MORNING MCS EXISTS NEAR FRONT -- PER DAY-1
OUTLOOK.  ISOLATED SEVERE WIND/HAIL POSSIBLE WITH THIS ACTIVITY
THROUGH MORNING HOURS. ASSOCIATED CLOUD/PRECIP FIELD MAY ALTER
EFFECTIVE FRONTAL POSITION AND/OR SPEED OF DIURNAL
DESTABILIZATION...SO SUCH UNCERTAINTIES COMPEL SOME BROAD-BRUSHING
OF SEVERE PROBABILITIES THIS REGION.

SCATTERED TO NUMEROUS TSTMS IN ONE OR MORE LINES ARE POSSIBLE DURING
AFTERNOON AND EVENING ALONG/AHEAD OF SFC BAROCLINIC ZONE.
ISALLOBARIC FORCING ASSOCIATED WITH MN CYCLOGENESIS WILL ENHANCE LOW
LEVEL VERTICAL SHEAR PROFILES ACROSS ADJOINING WARM SECTOR...OVER
UPPER MIDWEST. WIND DAMAGE APPEARS TO BE MAIN THREAT BASED ON
NEARLY UNIDIRECTIONAL WIND PROFILES AND BACKING WITH HEIGHT PROGGED
THROUGH MID-UPPER TROPOSPHERE. HOWEVER...IT IS TOO SOON TO RULE OUT
POTENTIAL FOR TORNADOES GIVEN BACKED FLOW E-NE OF DEEPENING SFC LOW
AND AT LEAST MARGINALLY FAVORABLE THERMODYNAMICS.  LOW-MID 60S SFC
DEW POINTS AND DIABATIC HEATING WILL YIELD 500-1500 J/KG MLCAPE IN
NARROW CORRIDOR JUST AHEAD OF FRONT.

SEVERE PROBABILITIES SHOULD DIMINISH WITH SWD EXTENT ALONG COLD
FRONT THROUGH IA/SERN NEB/NWRN MO/NERN KS AREA AS CONVERGENCE
WEAKENS...THEN INCREASE AGAIN WITH PROXIMITY TO S-CENTRAL HIGH
PLAINS CYCLONE.

...CENTRAL/SRN HIGH PLAINS...
CONVECTION SHOULD BREAK CAP DURING AFTERNOON INVOF SFC LOW...AND
PERHAPS IN FORM OF ISOLATED SUPERCELLS SWD ALONG DRYLINE THROUGH
PORTIONS WRN OK AND NW TX.  DRYLINE RELATED SEVERE PROBABILITIES
BECOME MORE CONDITIONAL AWAY FROM SFC LOW BECAUSE OF CAPPING AND
WEAKENING LOW-MIDLEVEL FLOW WITH SWD EXTENT.  WITH PRIMARY LARGE
SCALE FORCING REMOVED FROM THIS AREA...LOW LEVEL FLOW IS PROGGED TO
BE WEAK - GENERALLY 10 KT OR LESS IN BOUNDARY LAYER.  THIS WILL 
MITIGATE HODOGRAPH SIZE...THOUGH SOME STRONGER WINDS ARE LIKELY
CLOSE TO SFC LOW.  30-40 KT MIDLEVEL FLOW FROM RED RIVER NWD...AND
NEARLY 50 KT OVER SW KS...SUGGESTS SUPERCELL POTENTIAL.  8-9 DEG
C/KM MIDLEVEL LAPSE RATES AND 50S/LOW 60S F SFC DEW POINTS WILL
CONTRIBUTE TO 1500-2000 J/KG MLCAPE.

SEPARATE AREA OF SEVERE DEVELOPMENT POSSIBLE MID-LATE AFTERNOON OVER
PORTIONS ERN CO...W THRU NE OF SFC LOW AND BEHIND SFC COLD FRONT. 
ACTIVITY IN THIS REGION MAY BEGIN AS DISCRETE SUPERCELLS THEN SHIFT
EWD INTO PORTIONS WRN KS LATE AFTERNOON INTO EVENING AS TSTM
CLUSTER.  ALTHOUGH POST-FRONTAL CAA WILL REDUCE LOW LEVEL
INSTABILITY RELATIVE TO AIR MASS E OF DRYLINE. HOWEVER...
INSOLATION AND MOIST ADVECTION AMIDST NELY/ELY FLOW WILL YIELD
500-1000 MLCAPE BY MIDAFTERNOON.  BACKED POST-FRONTAL FLOW WILL
ENHANCE BOTH LOW LEVEL SHEAR AND LIFT...BY MEANS OF UPSLOPE
COMPONENT.

..EDWARDS.. 05/11/2004

...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.